1. Field of the Invention
The present invention relates to an optical element module containing a semiconductor laser element in a casing.
2. Description of the Related Art
In some cases, in an optical element module containing a semiconductor laser element such as an integrated semiconductor laser element or the like (see Japanese Laid-open Patent Publication No. 2011-35060) in a casing, a fluctuation in an ambient temperature causes a warp on a bottom plate of the casing and the warp affects an optical element. To address this, a technology of preventing the warp of the bottom plate from affecting the optical element is disclosed (see Patent Literatures of Japanese Laid-open Patent Publication Nos. 2010-258354, 2008-193003, 2002-131585 and 2009-267386).